Heretofore, a large number of molding materials comprising a filler and a fiber have been proposed as means of improving the mechanical strength such as stiffness and impact resistance of a polyolefin resin.
Due to a growing cry for environmental protection, lightweight parts are now strongly desired. As one of measures for this, it is proposed to improve the mechanical strength such as stiffness and impact strength of a polyolefin resin by mixing a polyester fiber.
For example, Patent Document 1 proposes a fiber-reinforced pellet containing a polyolefin resin as a matrix component and a synthetic organic fiber as a reinforcing fiber.
Patent Document 2, Patent Document 3 and Patent Document 4 propose resin compositions comprising a polyalkylene naphthalate (polyalkylene naphthalene dicarboxylate) fiber and a polypropylene resin as resin compositions having improved mechanical strength and heat resistance.
(Patent Document 1) JP-A 2001-49012
(Patent Document 2) JP-A 2005-272754
(Patent Document 3) JP-A 2006-8995
(Patent Document 4) JP-A 2006-233379
However, the resin compositions disclosed by the above publications are still unsatisfactory in terms of mechanical strength such as flexural strength and impact resistance.